When people ask if women can have it all, that's a boring question. When Rihanna asks whether she can have it all, she's talking about both wearing a bra and a shirt. She told Vogue that if she has either a bra or a shirt, that is sufficient for her:

If I’m wearing a top, I don’t wear a bra. If I’m wearing a bra, I just wear a bra.

Rihanna is a hedonist for our time. She's not greedy. She's not a mouse who asks for a cookie or a moose who wants a muffin. If she has one thing, she will not press her luck. Either a bra or a shirt, please. Don't trouble yourself to try to have everything.